When approaching from a road on the right (slip road): give way to traffic already on the motorway, accelerate in the extra lane, join the inside lane when you have the same speed as the traffic
Leaving:
When leaving by a road on the right: watch for the signs about your turn-off point, give a clear signal, get into the right lane and join the slip road in time
If you miss your turn-off point, carry on until the next one, do NOT reverse or turn back